Samsung said in November 2011 that Android 4.0 - aka Ice Cream Sandwich - will be coming to its Galaxy S II smartphone some time in 2012. It has yet to narrow that window, but industry leak merchant Eldar Murtazin has now said ICS will hit the S II in March.
Unsurprisingly, operator-tied handsets may have to wait a little longer …

It's available on a very limited amount of handsets like the Galaxy Nexus and Nexus S currently, along with a few tablets. You can get a hold of other builds based on CM9 code but CM9 has not been released fully yet. The main stumbling block seems to be camera related and they're waiting for drivers or source to be released so they can build the drivers. It's something like that anyway.

Quick note to mention that other builds based on CM9 are using a hacked in version of the Gingerbread camera to function and while it works most of the time it has issues (graphical artifacts showing on random pictures) and only supports basic image shooting right now. That means no camcorder or panorama mode and definitely no Zero Shutter Lag (ZSL) mode.

NEVER

Latest build already pretty good

Running the latest leaked build (LPB) for a couple of weeks now and it's pretty damn good. Battery life is waaay better than stock Gingerbread, and it's faster too. There are a few issues with wallpaper/gallery locking up, as well as Settings crashing when exiting Wi-Fi hotspot mode. On the whole though, it's rock solid, fast and power-efficient. I can only imagine Samsung will have made it even better by release time. =)

Bought mine at carphone warehouse

Mine was bought on contract with three, but it seems to be branded as carphone warehouse. (it was unlocked too, which was nice of them)

Apparently it's dependant on whoever branded it on what firmware you get and when. For example, the csc code on mine: I9100CPWKH1. (Note the CPW for carphone warehouse)

To find out your csc and who the phone is branded to, enter the following as you would dialing a phone number: *#1234#

Unfortunately carphone warehouse have a bit of a bad reputation for updates... (mine is still on android 2.3.4, whilst 2.3.5 has been out for a fair while now)

Frankly, I may just flash my phone using odin when the official samsung ICS update comes out. I'm not going to flash my phone with CM9 because that's still alpha/beta quality. And I don't want my custom flash counter incrementing. (it increments if you use unofficial roms, I like my warranty thanks)

2.3.4 is what firmware unbranded sgs2 are stuck at the moment, like mine from t mobile. I hAve already rooted my month old phone, and reset the count to 0 and removed warning triangle. Just couldn't live without root.

Interesting

Now that the manufacturers are releasing the updates, I wonder how long until Google/Samsung get around to releasing the update for my Nexus S. You know, the one with the unbranded Android... There was a limited run before Christmas (my firmware version wasn't included) that they quickly pulled and it's been very quiet since.

Hmmm... Not even a mention of the many 'leaked' beta versions and the considerable amount of development that has gone into them by xda-developers / Cyanogen team?

Nice to get the tip but this article is rather light on related info...

For example, Samsung's release will almost certainly replace the stock ICS launcher with their Touchwiz interface, a move which will be very unpopular with many and to some extent negate the very reason for upgrading to ICS!

Leaked builds

I've been running the leaked ICS builds for several weeks. It's now up to 4.0.3 and definitely a huge improvement. The best feature of ICS has to be the ability to freeze unwanted apps. Previously you needed root + titanium backup to remove carrier bloatware.